Directionally targeted jet noise reduction system and method

Abstract

An exemplary engine noise reduction system, can be provided, which can include a noise reduction fluid source, and a microjet(s) placed at an axial location downstream from a nozzle exit of an engine and configured to asymmetrically inject a noise reduction fluid from the noise reduction fluid source into a jet flow of the engine. The engine can be a jet engine. The microjet(s) can include four microjets, which can be about 90 degrees apart in a plane at the axial location. The four microjets can be asymmetric microjets. The microjet(s) can be configured to inject the noise reduction fluid in a direction that is normal with respect to the jet flow.

What is claimed is: 
     
       1. An engine noise reduction system, comprising:
 a noise reduction fluid source; and 
 at least one microjet (i) placed at an axial location downstream from a nozzle exit of an engine, (ii) placed on at least one of a center body of the engine or an injection tube on an axis of the engine, and (iii) configured to asymmetrically inject a noise reduction fluid from the noise reduction fluid source into a jet flow of the engine. 
 
     
     
       2. The engine noise reduction system of  claim 1 , wherein the engine is a jet engine. 
     
     
       3. The engine noise reduction system of  claim 1 , wherein the at least one microjet includes four microjets. 
     
     
       4. The engine noise reduction system of  claim 3 , wherein the four microjets are about 90 degrees apart in a plane at the axial location. 
     
     
       5. The engine noise reduction system of  claim 3 , wherein the four microjets are asymmetric microjets. 
     
     
       6. The engine noise reduction system of  claim 1 , wherein the at least one microjet is configured to inject the noise reduction fluid in a direction that is normal with respect to the jet flow. 
     
     
       7. The engine noise reduction system of  claim 1 , wherein the at least one microjet has a circular shape. 
     
     
       8. The engine noise reduction system of  claim 1 , wherein the at least one microjet is concentric with the engine. 
     
     
       9. The engine noise reduction system of  claim 1 , wherein the at least one microjet is configured to inject the noise reduction fluid in a non-parallel direction with respect to the jet flow. 
     
     
       10. The engine noise reduction system of  claim 1 , wherein the noise reduction fluid includes a high momentum fluid. 
     
     
       11. The engine noise reduction system of  claim 1 , wherein the at least one microjet is configured to inject the noise reduction fluid radially outward from a centerline or the axis. 
     
     
       12. The engine noise reduction system of  claim 1 , wherein the at least one microjet includes a plurality of microjets, and wherein at least two of the at least one microjet are asymmetrically distributed on the at least one of the center body of the engine or the injection tube on the axis of the engine. 
     
     
       13. The engine noise reduction system of  claim 1 , wherein the at least one microjet includes a plurality of microjets, and wherein at least one of an injection pressure or an injection flow rate of the noise reduction fluid is different between at least two of the plurality of microjets. 
     
     
       14. A jet engine noise reduction system, comprising:
 at least one jet engine; and 
 at least one microjet (i) placed at an axial location downstream from a nozzle exit of the at least one jet engine, (ii) placed on at least one of a center body of the at least one jet engine or an injection tube on an axis of the at least one jet engine, and (iii) configured to asymmetrically inject a noise reduction fluid into a jet flow of the at least one jet engine. 
 
     
     
       15. The jet engine noise reduction system of  claim 14 , wherein the at least one microjet includes four microjets placed about 90 degrees apart in a plane at the axial location. 
     
     
       16. The jet engine noise reduction system of  claim 14 , wherein at least one microjet is configured to inject the noise reduction fluid in a direction that is normal with respect to a jet flow of the jet engine. 
     
     
       17. The jet engine noise reduction system of  claim 14 , wherein at least one jet engine has a serrated edge. 
     
     
       18. The jet engine noise reduction system of  claim 14 , wherein the at least one microjet is configured to inject the noise reduction fluid in a non-parallel direction with respect to the jet flow. 
     
     
       19. The jet engine noise reduction system of  claim 14 , wherein the noise reduction fluid includes a high momentum fluid. 
     
     
       20. The jet engine noise reduction system of  claim 14 , wherein the at least one microjet is configured to inject the noise reduction fluid radially outward from a centerline or the axis. 
     
     
       21. A method for reducing noise from a jet engine, comprising:
 providing at least one microjet placed on at least one of a center body of the jet engine or an injection tube on an axis of the jet engine; and 
 asymmetrically injecting a noise reduction fluid into a jet flow of the jet engine at an axial location downstream from a nozzle exit of the jet engine. 
 
     
     
       22. The method of  claim 21 , wherein the at least one microjet includes four microjets. 
     
     
       23. The method of  claim 22 , wherein the four microjets are about 90 degrees apart in a plane at the axial location. 
     
     
       24. The method of  claim 21 , wherein the asymmetrically injecting the noise reduction fluid includes asymmetrically injecting the noise reduction fluid in a direction that is normal with respect to the jet flow. 
     
     
       25. The method of  claim 21 , wherein the noise reduction fluid is radially injected radially outward from a centerline or the axis.